Gas and oil well pumping or swabbing devices to remove oil from an oil and gas well relying on the residual gas pressure in the well to lift the swabbing device and the attendant column of oil thereabove in said oil well casing are exemplified by U.S. Pat. Nos. 4,813,485, Coyle, 4,528,896, Edwards, 4,070,134, Gramling, and 3,179,022, Bloudoff, as well as others. Many of these devices contain a valve which, when open, permits the inherent weight of the swabbing device to cause it to sink down within the oil well casing through the accumulated oil and gas therein to a predetermined position near the bottom of the casing, at which time a stop or a pressure sensor will cause the valve to be closed, and as gas pressure builds up underneath the swabbing device, it and the column of oil thereabove will be raised to the surface, at which time the valve will again be opened, either automatically or manually, and the swabbing device will repeat the cycle.
There are a number of stops for actuating the valve in the swabbing device disclosed in the prior art, some of which are retrievable. However, many are not. Examples of these stops are U.S. Pat. Nos. 3,102,594, Crowe, 3,812,911, Vann, 4,113,010, Gramling, 4,405,017, Allen, et al., and others.
In the extremely low yield oil wells in which these pumping devices are used, the removable stops are, for the most part, expensive and complicated, and the ones that are economically attractive for such use remain in the well, which is undesirable.